The development of integrated circuit technology from small scale integration to very large scale integration as well as the development of various hybrid integrated circuit packages has had great technological and economic impact on the U.S. electronics industry. The various individual integrated circuits as well as other components such as capacitors, resistors and the like are generally packaged in a circuit pack assembly. The circuit pack assemblies are protected from moisture and other contaminants by encapsulating them with a protective polymeric encapsulant material. One often used type of encapsulant is a silicone encapsulant, such as an RTV (room temperature vulcanized) silicone encapsulant. Circuit pack assemblies known as single-in-line packaging, dual-in-line packaging and hybrid integrated circuit packages are typical circuit pack assemblies which may be found to be encapsulated in such a protective polymeric material.
One problem that arises during the manufacture of circuit pack assemblies is that small metal particles which are formed when excess lengths of circuit leads which extend from the circuit packs are clipped after insertion into a printed wiring board. These metal pieces tend to stick to silicone encapsulated assemblies resulting in various quality control problems. We have found that static charge on the surface of the silicone encapsulant polymer as well as some tackiness of the surface have been the major causes of the problem. It has now been discovered that by the addition of a simple step subsequent to encapsulation and prior to insertion in the substrate and clipping of the leads one can substantially eliminate the tackiness and static charge problems.